Do 40V Ryobi Tool Batteries Work On 80V Lawn Mowers?

One of the hallmarks of the Ryobi power tool line is the interconnectivity. The bulk of its tools run on 18-volt batteries, which, regardless of amperage, will run the tool without trouble. Moving up in voltage, though, things can get a bit hazier. For example, Ryobi has a line of larger tools and appliances, predominantly lawn mowers, that require 80 volts to run, and the brand does sell 80V batteries to get them moving. However, the question to ask is if you're in a jam and only have two 40V batteries lying around, is there a way to use them to run your 80V mower?

On paper, this seems like it should work. Two 40V batteries means a cumulative 80V, so they should have no trouble running an 80V mower together. Not to mention, some Ryobi 80V lawn mowers have multiple slots in the battery compartment for 40V units. The fact is, though, these Ryobi products aren't designed to run on 40V batteries alone. Ryobi has explained that its 80V items, like the aforementioned lawn mowers, are specifically intended to operate with an 80V battery attached. Without it, the mower won't start, even if there are two 40V batteries present. Thus, this is another instance where knowing how to find the right battery for your Ryobi tool is essential.

With all of that said, this isn't quite where the story ends. 40V batteries can connect to 80V mowers, and while they can't run such an appliance on their own, they and the tools themselves can benefit from such a connection.

Overall, a pair of 40V batteries isn't going to run an 80V tool. In some circumstances, though, and in specific appliances, 40V batteries can help out. Ryobi has explained that in its 80V lawn mower models, 36V batteries — basically interchangeable with 40V, as it turns out — can be inserted alongside an 80V battery as supplementary power. The idea is to lengthen runtime if you need to keep your mower going longer than the 80V battery alone can provide. A 36V/40V battery, or even up to three in some cases, simply slots and clicks right into the battery compartment as an 80V battery booster.

Additionally, power can flow in the opposite direction in making such a connection. You can actually charge a 40V battery while it's inside an 80V mower, just as you would the 80V battery itself. Ryobi 80V mowers have an on-board charging ability; this way, you don't have to remove the 80V battery every time it needs a recharge. A 40V battery can also take advantage of this feature once inserted correctly into the battery compartment. Better yet, the plugged-in mower will charge the batteries simultaneously, so if you need both at their peak to get started on your next job, you don't have to wait around for one while the other juices up.

Though they can't run an 80V Ryobi product on their own, 40V batteries aren't entirely useless in such a context. They can keep you on the job longer, or they can jump into the battery compartment to charge up, either to act as an 80V battery booster or to run their own line of tools.